On Wed, Nov 14, 2018 at 10:17:00PM +0100, David Hildenbrand wrote: > Rename PG_balloon to PG_offline. This is an indicator that the page is > logically offline, the content stale and that it should not be touched > (e.g. a hypervisor would have to allocate backing storage in order for the > guest to dump an unused page). We can then e.g. exclude such pages from > dumps. > > In following patches, we will make use of this bit also in other balloon > drivers. While at it, document PGTABLE. Thank you for documenting PGTABLE. I didn't realise I also had this document to update when I added PGTABLE. > +++ b/Documentation/admin-guide/mm/pagemap.rst > @@ -78,6 +78,8 @@ number of times a page is mapped. > 23. BALLOON > 24. ZERO_PAGE > 25. IDLE > + 26. PGTABLE > + 27. OFFLINE So the offline *user* bit is new ... even though the *kernel* bit just renames the balloon bit. I'm not sure how I feel about this. I'm going to think about it some more. Could you share your decision process with us? I have no objection to renaming the balloon bit inside the kernel; I think that's a wise idea. I'm just not sure whether we should rename the user balloon bit rather than adding a new bit.
